JPH02238372A - Current detector - Google Patents

Abstract

PURPOSE:To obtain a small-sized current detector by a construction wherein a current to be measured is made to flow through a conductor layer provided on a base and a magnetic field generated in parallel with the upper side of the base is detected by a magnetoelectric conversion element mounted on the upper side of the base. CONSTITUTION:A base 12 has a conductor pattern 23, external connection terminals 24 and a mounting stage 25 provided on a metal plate 22 with an insulating layer 13 interlaid, and a magnetoelectric conversion element 14 and an amplifier circuit element 27 are attached on the stage 25. Covering is made selectively with an insulating layer 26, and the element 14, the terminals 24 and the element 27 are connected by metal wires 28 and then sealed up by a sealing material 29. Subsequently, a permanent magnet 15 for impressing a bias magnetic field Hb is provided on the lower side of the metal plate 22 and sealed up integrally by a molding member 30, and these components are accommodated in a shield case 31 of a magnetic material. When a current (i) is made to flow from the left to the right of the metal plate 22, a magnetic field Hk is generated in parallel with the upper side of the base 12 and at a right angle to the surface of this paper. The magnetoelectric conversion element 14 given the bias magnetic field Hb intersecting the Hk perpendicularly by the magnet 15 detects the Hk and this is taken out from the terminal 24 through the amplifier circuit 27. This small-sized current detector can be mounted on a printed circuit board in the same way as various circuit elements.

Description

[Detailed Description of the Invention] [Summary] This invention relates to the configuration of a current detector in which a magnetoelectric transducer is mounted on a substrate provided with a conductor layer through which a current to be measured flows, and which enables detection of large currents and is suitable for printed wiring boards, etc. Aiming at miniaturization for mounting, a magnetic field to be measured generated in a direction parallel to the upper surface by the current to be measured flowing through the conductor layer is converted into magnetoelectricity on the upper surface of the substrate having a conductor layer through which the current to be measured flows. A magnetoelectric transducer is mounted in an electrically insulated state from the conductor layer, and bias magnetic field generating means is provided for applying a bias magnetic field in a direction perpendicular to the magnetic field to be measured to the magnetoelectric transducer, and at least the substrate and the magnetoelectric transducer are mounted. and a bias magnetic field generating means are housed in a shield case for shielding external magnetic fields, and the conductor layer is a metal plate, and the substrate has an insulating layer on the upper surface of the conductor layer metal plate. a layer, and at least the magnetoelectric transducer is mounted on the insulating layer, or the conductive layer generates the magnetic field to be measured in a direction parallel to the upper surface of the substrate when the current to be measured flows. further comprising a pair of coil portions arranged on the substrate, the substrate comprising the conductor layer having the pair of coil portions on an insulating plate, and the magnetoelectric conversion element being mounted between the pair of coil portions facing each other; , a circuit element comprising at least an amplifier for amplifying the output of the magneto-electric transducer is formed on the substrate on which the magneto-electric transducer is formed.

[Industrial application field]

The present invention includes a substrate having a conductor layer through which a current to be measured flows, and a magnetoelectric transducer that detects a magnetic field generated in a direction parallel to the upper surface of the substrate when the current to be measured is passed through the conductor layer.
This invention relates to the configuration of a small current detector that can be mounted on a printed wiring board, etc.

Current detectors are used for motors such as magnetic disk devices and printers.
It is used for actuator systems, but in recent years, with the miniaturization of these devices and their peripheral equipment and the surface mounting of component circuit parts, current detectors have been miniaturized so that they can be surface mounted on printed wiring boards, etc. , has become strongly requested.

[Conventional technology]

2. Description of the Related Art Current detectors are known that measure the magnetic field created by a current to be measured flowing through a conductor and determine the strength of the current from the measured value.

FIG. 9 is a perspective view showing the basic structure of a conventional current detector, and FIG. 10 is a perspective view showing the basic structure of another conventional current detector.

FIG. 9 shows that the cut core 2 receives the magnetic field created by the current i flowing through the conductor 1, the strength of the magnetic field is measured by the magnetoelectric transducer 3, and the strength of the current i flowing through the conductor 1 is determined from the measurement. I can do it.

FIG. 10 shows a configuration in which, when a current i is passed through the conductor 4, the magnetoelectric transducer 5 directly receives the magnetic field generated in the middle part 4a of the conductor 4 formed in a U-shape.
The U-shaped intermediate portion 4a and the magnetoelectric transducer 5 are housed in a shield case 6 shown by broken lines so as not to be affected by external magnetic fields.

[Problem to be Solved by the Invention] In the above-mentioned conventional technology, the one using the cut core 2 has a configuration in which the conductor 1 through which the current to be measured passes through the cut core 2, so that the printed wiring board has no surface area. There is a problem that it cannot be mounted, and the one in which the current to be measured i flows through the conductor 4 whose intermediate part 4a is formed into a U-shape can be made smaller than the one using the cut core 2, but it is not suitable for surface mounting. There is a problem in that the current detector is larger than other mounted circuit components, and it is necessary to solve this problem in a small current detector for surface mounting.

[Means to solve the problem]

FIG. 1 is a basic configuration diagram of a current detector according to the present invention.

In FIG. 1, a current detector 11 includes an insulating layer 1 on the upper surface of a substrate 12 having a conductor layer through which a current i to be measured flows in a predetermined direction.
A magnetoelectric conversion element 14 for magnetoelectrically converting a magnetic field to be measured Hk generated in a direction parallel to the upper surface by a current to be measured i flowing through the conductor layer is mounted on the conductor layer in an electrically insulated state from the conductor layer. A bias magnetic field generating means 15 is provided to apply a bias magnetic field Hb in a direction orthogonal to the measurement magnetic field Hk to the magnetoelectric transducer 14, and at least the base 12, the magnetoelectric transducer 14, and the bias magnetic field generating means 15 are protected by a shield for blocking external magnetic fields. case 16
The conductor layer is a metal plate, and the substrate 12 has an insulating layer 13 on the upper surface of the metal plate.
is provided, and at least a magnetoelectric transducer 14 is provided on the insulating layer 13.
Alternatively, the conductor layer includes a pair of coil portions that generate a magnetic field to be measured Hk in a direction parallel to the upper surface of the substrate when the current to be measured i flows therethrough, and the substrate 12 is The conductive layer having the pair of coil portions is provided on an insulating plate, and the magnetoelectric conversion element 14 is mounted between the pair of coil portions facing each other. The structure is characterized in that a circuit element including at least an amplifier for amplifying the output of the magnetoelectric conversion element 14 is formed on the formation substrate.

[Effect]

According to the above means, a current to be measured is passed through a conductor layer provided on a substrate, and a magnetic field to be measured generated by the current to be measured is generated in a direction parallel to the top surface of the substrate using a magnetoelectric transducer mounted on the top surface of the substrate. By adopting a detection configuration, we have realized a compact current detector that can be mounted on printed wiring boards in the same way as various circuit elements, making it possible to incorporate the current detector into various circuits.

〔Example. ]

The current detector according to the present invention will be explained below using the drawings. FIG. 2 is a cross-sectional view (A) schematically showing the main structure of the current detector according to the first embodiment of the present invention, and a plan view (0) showing the arrangement of mounted elements mounted on the substrate of the current detector. , FIG. 3 is a circuit diagram of the current detector shown in FIG. 2, and FIG. 4 is a diagram for explaining the main manufacturing process of the current detector shown in FIG. 2.

In the current detector 21 shown in FIG. 2, in which the same reference numerals are used for parts common to those in FIG. 23, an external connection terminal 24, and a mounting stage 25, and a magnetoelectric transducer 14 and a circuit element 27 for amplifying the output of the magnetoelectric transducer 14 are mounted on the pair of mounting stages 25.

The conductor pattern 23 with the insulating JllW 26 formed thereon and the magnetoelectric transducer 14. The terminal 24 on which the insulating layer 26 is formed and the circuit element 27 are connected to each other by a metal wire 28 so that the main parts are exposed, and then the magnetoelectric transducer 14 etc. are sealed with a sealing material 29, and then the metal It is sealed with a mold member 30 together with a permanent magnet (bias magnetic/field generating means) 15 for applying a bias magnetic field Hb disposed on the lower surface of the plate 22, and these are housed in a shield case 31 made of a magnetic material.

In such a current detector 21, when a current to be measured i is passed from the left end to the right end of the metal plate 22 as shown in FIG. A magnetic field Hk to be measured in the width direction is generated, and the magnetoelectric transducer 14, which is mounted so as to detect a magnetic field in the same direction as the magnetic field Hk and is given a bias magnetic field Hb in a direction perpendicular to the magnetic field Hk by a permanent magnet 15, converts the magnetic field Hk. The output of the magnetoelectric conversion element 14 detected and amplified by the circuit element 27 is taken out from the output terminal 24.

In Figure 3, the bias magnetic field H is configured as a full bridge.
The output terminal of the magnetoelectric conversion element 14 given b is connected to a circuit element 27 including a differential amplifier 32, etc., and a constant current source and an ammeter are connected between the pair of input terminals 33 of the magnetoelectric conversion element l4. is connected. The output of the magnetoelectric transducer 14 generated by applying the magnetic field to be measured Hv in the direction perpendicular to the bias magnetic field Hb is amplified by a factor of 100, for example, through the circuit element 27.
A digital multimeter or X- connected to the output terminal 24
It will be measured and recorded using a Y recorder or the like.

4(a) to (2), after the insulating layer 13 and the conductor film 34 are deposited on the upper surface of the metal plate 22, unnecessary parts of the conductor film 34 are removed by etching, and the conductor pattern 23 and the terminal 24 are removed.
and a stage 25, and a conductive pattern 23 and a terminal 2.
4, the connecting portion of the metal wire 28 is left and covered with an insulating layer 26. Next, the magnetoelectric transducer 14 is mounted on the pair of stages 25.
After mounting the and circuit elements 27, each conductor pattern 23
one end, the magnetoelectric conversion element 17 and each conductor pattern 23
The other end and the circuit element 27 and the terminal 24 and the circuit element 2
7 with a metal wire 28.

After that, a sealing material 29 is formed on the upper surface of the metal plate 22,
A permanent magnet (or a magnet with a thin film structure) is attached to the bottom surface of the metal plate 22.
After gluing 15, they are covered with a mold member 30 as shown in FIG.

FIG. 5 is a sectional view schematically showing the main structure of a current detector according to a second embodiment of the present invention, and FIG. 6 is a plan view (A) and a sectional view (A) of a substrate according to a third embodiment. If), 7th
The figures are a plan view (a) and a cross-sectional view (opening) of a substrate according to the fourth embodiment.

In FIG. 5, in which the same reference numerals are used for parts common to the previous figure, the substrate 12 of the current detector 41 has an insulating plate 42 glued to the upper surface of the metal plate 22, and a conductive pattern 2 on the insulating Jli 42.
3, a terminal 24 for external connection, and a mounting stage 25. On the pair of mounting stages 25, there is a magnetoelectric transducer 14 and a circuit element 27 for amplifying the output of the magnetoelectric transducer 14.
will be installed.

The conductor pattern 23 and the magnetoelectric transducer 14 on which the insulating layer 26 is formed so that the main part is exposed, and the terminal 24 and the circuit element 27 on which the insulating layer 26 is formed so that the main part is exposed are connected by a metal wire 28. After each connection is made, the magnetoelectric transducer 14 and the like are sealed with a sealing material 29, and then a permanent magnet (or thin film magnet) 15 for applying a bias magnetic field HbO is positioned above the magnetoelectric transducer 14, and the mold member 30 is sealed. A shield case 31 made of a magnetic material is formed.
be accommodated in.

In FIG. 6, the base 12 is formed by forming a conductor layer 46 on the upper surface of an insulating plate 45. As shown in FIG. The conductor layer 46 has a pair of coil parts 46
a, 46b and terminals 46c, 46d. A coil portion 46a is formed to sandwich the insulating layer 47 in its thickness direction. 46b, a conductive pattern 46e formed on the lower part of the insulating layer 47, a conductive pattern 46f formed on the upper part of the insulating layer 47, and the terminals 46c, 46d are connected through a via hole 46'g.

The base 12 provided with such a conductor layer 46 is
When a current to be measured i is passed through the current i, a magnetic field to be measured Hk generated by the current i is applied to the substrate 1 in the magnetoelectric transducer mounting area 48 shown by the dashed line between the coil portions 46a and 46b.
2 and in the width direction of the base 12, and its magnetic field {k is larger than that of the metal plate 22 described above.

In FIG. 7, in which the same reference numerals are used for parts common to those in FIG. 6, the substrate 12 has a conductor N50 formed on the upper surface of an insulating plate 45. The conductor layer 50 includes a pair of terminals 50a and 50b formed on an insulating layer 51 formed on the upper surface of an insulating plate 45, and a spiral coil portion 50c. 50d, a pair of coil parts 5
0c. The center end of 50d is connected by a conductor pattern 50e formed at the bottom of the bottom part 51.

The base 12 having such a conductor Ji 50 has a conductor layer 5
When the current to be measured i is passed through the coil parts 50c and 50
The polarity (N and S) is reversed in the central part of d, so that in the magnetoelectric transducer mounting area 48 shown by the dashed line between the coil parts 50b and 50c, the center part is parallel to the upper surface of the substrate 12 and is parallel to the upper surface of the substrate 12.
A magnetic field Hk to be measured is generated in the width direction of the conductor layer 2, and the magnetic field Hk can be made larger than that of the conductor layer 46 described above.

FIG. 8 is a plan view schematically showing a configuration in which a magnetoelectric conversion element and a circuit element are integrated according to a fifth embodiment of the present invention, and an element 60 mounted on the substrate 12 is made of silicon or the like. On the element substrate 61, a magnetoelectric conversion element (magnetoresistive element) 14 with a full bridge configuration shown in FIG. This is a configuration in which they are connected in a pattern 62.

Such an element 60 is a combination of the magnetoelectric transducer 14 and the circuit element 2.
The current detector is smaller than the one in which the elements 7 are configured separately, and is therefore equipped with an element 60 in place of the magnetoelectric transducer 14 and circuit element 27 in FIGS. 2 and 5, and the element in FIGS. 6 and 7. The current detector in which the element 60 is mounted in the mounting area 48 has the advantage that it is smaller than one in which the magnetoelectric conversion element 14 and the circuit element 27 are mounted, and requires less effort to mount it on the base vi12.

〔Effect of the invention〕

As explained above, in the current detector of the present invention, a current to be measured is passed through a conductor layer provided on a substrate, and a magnetic field to be measured generated by the current to be measured is generated in a direction parallel to the top surface of the substrate. By configuring the current detector to be detected using a magneto-electric transducer mounted on the sensor, a compact current detector that can be mounted on a printed wiring board has been realized, making it possible to incorporate it into various circuits.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the current detector of the present invention, FIG. 2 is a current detector according to the first embodiment of the present invention, FIG. 3 is a circuit diagram of the current detector shown in FIG. 2, and FIG. The figure is an explanatory diagram of the main manufacturing process of the current detector shown in Figure 2, Figure 5 is a current detector according to the second embodiment of the present invention, and Figure 6 is an illustration of the current detector according to the third embodiment. 7 shows the substrate of the current detector according to the fourth embodiment, FIG. 8 shows the mounted elements of the current detector according to the fifth embodiment of the present invention, and FIG. 9 shows the components of the conventional current detector. Basic configuration diagram. Figure 10 is a basic configuration diagram of a current detector according to another conventional technology. In the figure, 11 is a current detector, 12 is a substrate, 13 is an insulating layer, 14 is a magnetoelectric conversion element, 15 is a magnetic field generating means (permanent magnet), 16 is a shield case, 22, 46, 50 are conductor layers (metallic 27 is a circuit element, 45 is an insulating plate, 46a, 46b, 50b,
50c is a coil portion, 61 is an element substrate, Hb is a bias magnetic field, HK is a magnetic field to be measured, and i is a current to be measured. Wa unexploded e month's current detector's toad moat box map % 1 Figure Tamura 2 5 CS nail τ curvature detector's 5D Rei map
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Claims (4)

[Claims] (1) Conductor layer (22, 46,
on the top surface of the substrate (12) having the conductor layer (22).
, 46, 50) is connected to the conductor layer (22, 46, 50).
50), and a bias magnetic field (Hb) in the direction perpendicular to the magnetic field to be measured (Hk).
) to the magnetoelectric transducer (14), and isolates at least the substrate (12), the magnetoelectric transducer (14), and the bias magnetic field generator (15) from external magnetic fields. A current detector characterized in that the current detector is housed in a shield case (16). (2) The conductor layer (22) is a metal plate, and the substrate (
12) is an insulating layer (13) on the top surface of the metal plate conductor layer (22).
), and at least the magnetoelectric conversion element (14) is mounted on the insulating layer (13). (3) The conductor layer (46, 50)
), which generates the magnetic field to be measured in a direction parallel to the upper surface of the substrate (46a, 46b).
, 50c, 50d), the substrate (12) comprising the conductor layer (46, 50) having the pair of coil portions (46a, 46b, 50c, 50d) on an insulating plate (45), The magnetoelectric transducer (14) is connected to the pair of coil portions (46a).
, 46b, 50c, 50d). 46b, 50c, 50d). (4) A circuit element (27) comprising at least an amplifier for amplifying the output of the magnetoelectric transducer (14) is formed on the substrate (61) on which the magnetoelectric transducer (14) is formed. The current detector according to claim 1, 2 or 3.